Underwater acoustics positioning using surface multipath

A new acoustic navigation method is proposed which utilizes surface reflected signals for position fixing. In this method, precise angular measurements of arrival angles of direct path and multipath signals are performed and used to find the relative position of the source. Reflection from a rough surface is considered, and the effect on nonspecular scattering is discussed. The main advantage of this approach is that the acoustic source can be a free running pinger rather than a transponder. This reduces the system´s complexity and cost. Furthermore, the bandwidth of the system can be considerably reduced, and therefore its range can be increased.<>